1. Field of the Invention
The present invention relates to a method of desensitizing hypersensitive dentin, and, more particularly, to a method of desensitizing hypersensitive dentin by continuously constricting or occluding the dentinal tubules in the tooth dentin.
2. Background Art
Hypersensitive dentin symptom is a malady accompanied by pain in the dentin which has been exposed due to various reasons and is stimulated by cold water, rubbing, or the like. In recent years, along with the progress of prolongation of life-span, an increasing number of people are suffering from gingiva degeneration and paradentitis. The trend magnifies the clinical significance of hypersensitive dentin. The hydraulic dynamism theory is currently predominant as the cause of hypersensitive dentin. According to this theory, the stimuli conveyed through dentinal tubules irritates nerves distributed over dental pulp and tooth dentin, causing a pain in these areas. Suppressing hypersensitive dentin and ameliorating or alleviating the pain are considered to be achieved by sealing dentinal tubules which is the consciousness conductor by physical or chemical means, or by fixing the dentinal tubules with proteins.
Therapeutic means for desinsitizing hypersensitive dentin have been reported by J. F. Collins et al [J. Periodontol, 55, 720 (1984)] relating to dentifrices containing sodium citrate and U.S. Pat. No. 3,689,636 relating to compositions containing a water-soluble chloride such as calcium chloride, magnesium chloride, and potassium chloride.
The above therapeutic means using water-soluble metal ions, however, have drawbacks in that (1) the effects do not last long, (2) the chemicals irritate to dental pulp, (3) the chemicals produce unfavorable taste, (4) the chemicals cannot be used in conditions at near-neutral levels because precipitation of hydroxides occurs, and the like.
In view of this situation, the present inventors have undertaken extensive studies in order to develop a method of desensitizing hypersensitive dentin which is free from the above-described drawbacks (1)-(4). As a result, the present inventors have found that application of a colloid produced by mixing a polyvalent metal salt and a polyol phosphate in an aqueous medium to teeth can continuously constrict or occlude dentinal tubules in the tooth dentin, without complications, such as production of precipitates in the neighborhood of neutral, and the like. This finding has led to the completion of the present invention.